Design

Setting

3 health maintenance organizations (HMOs) in the United States.

Patients

407 patients (mean age 45 y, 77% women) who were frequent users of general medical
care (> 85th percentile for the number of outpatient visits in each of the
previous 2 years) and were depressed (Hamilton Depression Rating Scale [HDRS] score
≥ 15). Exclusion criteria included active treatment for depression in previous
90 days or contraindications to depression treatment. Analyses included 92% of patients
for health care use and 91% for cost-effectiveness.

Intervention

{82}‡ physician practices were allocated to a DMP (n = 218), and {81}‡ were allocated to usual care (n = 189). DMP consisted of patient and physician education and telephone-care
management, antidepressant treatment for most patients, and psychiatric consultation
for nonresponders.

Main cost and outcome measures

The main outcome was number of depression-free days (estimated by interpolation).
Direct costs were assessed for all services provided or paid for by health plans in
1996 U.S. dollars. Costs for time in treatment were estimated as lost wages. Results
were adjusted for age, sex, study site, baseline measures of depression severity and
health status, and clustering of patients by physicians.

Main results

The DMP group had more depression-free days than did the usual-care group (229.3 vs
181.9 d; mean adjusted difference 47.4 d, 95% CI 26.6 to 68.2 d). The Table shows
the incremental costs of the DMP relative to usual care.

Conclusions

In depressed patients who are frequent users of general health care, a depression-management
program was effective for improving clinical outcomes at increased health-services
cost. Outpatient and inpatient services each cost approximately $20 per additional
depression-free day.

Commentary

Depressive illness is common and disabling and is mostly managed in primary care without
recourse to specialist services. Received wisdom is that management is suboptimal:
Up to 50% of depressive conditions are missed by practitioners, and treatment of diagnosed
patients is of inadequate intensity and duration. Educational interventions for practitioners
that use clinical guidelines to improve recognition and management have been evaluated,
but they have shown no benefit.

At least 3 hypotheses may explain this failure: Education may be insufficient to change
practitioner behavior, study design may have been inadequate to detect true benefit,
or the principles on which guidelines are based may be at fault. The last reason is
likely because most of the evidence base comes from secondary care, reflecting a lack
of research in primary care. “Sensitivity” of practitioners has been emphasized at
the expense of “specificity,” which may result in a failure to target patients who
would benefit most from more intensive management.

The studies by Katzelnick and Simon and their colleagues report the efficacy and cost-effectiveness
of a practice-based intervention to improve depression management in the managed-care
context of 3 U.S. HMOs. In a 2-stage screening procedure, patients with consultation
rates above the 85th percentile for ≥ 2 years were identified, and those in
whom evidence existed of untreated depressive disorder (Diagnostic and Statistical Manual of Mental Disorders, 4th edition [DSM-IV], diagnosis and HDRS score ≥ 15) were recruited (about 5% of the total registered
population). Half the sample had ≥ 1 comorbid chronic physical illness, presumably
accounting in part for their high consultation rates. The study had high completion
rates, but only patients enrolled with the HMO for ≥ 2 years were eligible.
This study characteristic limits the generalizability of the work to other settings
(such as general practice) and biases the results against such groups as the long-term
unemployed or the elderly.

DMPs have already been shown to benefit unselected depressed patients in primary care.
In this study, patients in the DMP had better outcomes than did those receiving usual
care, with significantly greater reductions in depression scores and higher quality-of-life
ratings. The authors estimate a number needed to treat of 5 to achieve 1 additional
remission, although it is not clear how remission was defined for this calculation.
The 2 studies were screening studies, however, and the “number needed to screen” to
achieve 1 additional remission is close to 17. Consultation rates in the intervention
group increased, whereas those in the usual-care group decreased slightly.

It is not possible to identify which component of the program was most beneficial,
but it seems probable on clinical grounds that the initial visit for assessment and
initiation of management (which did not occur in the usual-care group) would have
had considerable effect.

In analyzing the cost-effectiveness of the program, the construct of “depression-free
days” was used. It is important to understand how these days were derived. As depression
scores were only assessed at 6 weeks and 3, 6, and 12 months, most of the data were
interpolated. HDRS scores ≤ 7 were taken as “depression-free” (score 0), whereas
scores ≥ 22 were taken as “fully symptomatic” (score 1). Linear interpolation
was used to model recovery, allowing calculation of a number between 0 and 1 for each
day; “depression-free days” were then calculated by dividing the total scores by the
number of days in the period between estimates. This construct is clearly notional,
and its name is misleading because many of the periods contained no true depression-free
days, only partially depression-free days.

The costs of the intervention appear high, and no evidence existed of the hoped-for
“cost offset” effect by reduction in other sources of health care costs, perhaps not
surprising given the high prevalence of comorbid physical illness. The authors observe
that the study was insufficiently powered to compare frequency of inpatient admission,
which is costly; this lack might have led to failure to detect benefits. The study
also had only a 1-year follow-up, and benefits may take longer to be detected.

The clinical bottom line is that it is possible to identify unmet needs and improve
outcomes in this segment of the primary care population, but substantial additional
resources are required. Although these are not out of line with the costs of treating
other important conditions, priorities have to be established to permit shifting of
existing resources away from other therapeutic areas or investment of greater resources
in this one.